An TS3 server instance does usually host hundreds virtual server. On a dedicated server/computer there can be several TS3 server instances which host again several virtual TS3 servers. The server instances are distinguished by the TCP query port and the virtual servers by the UDP port.
The server instance does with this error message say, that it doesnt host/know the requested virtual server.
- the provided UDP port is incorrect
- the provided TCP query port is incorrect